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排序方式: 共有121条查询结果,搜索用时 31 毫秒
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P. Hartogh E. Lellouch M. Banaszkiewicz E.A. Bergin N. Biver M.I. Blecka D. Bockelée-Morvan J. Cernicharo G. Davis P. Encrenaz A. González T. de Graauw D. Hutsemékers E. Jehin M. Kidger A. de Lange D.C. Lis J. Manfroid R. Moreno G. Orton M. Rengel M. Sánchez-Portal S. Sidher B. Swinyard N. Thomas B. Vandenbussche C. Waelkens 《Planetary and Space Science》2009,57(13):1596-1606
“Water and related chemistry in the Solar System” is a Herschel Space Observatory Guaranteed-Time Key Programme. This project, approved by the European Space Agency, aims at determining the distribution, the evolution and the origin of water in Mars, the outer planets, Titan, Enceladus and the comets. It addresses the broad topic of water and its isotopologues in planetary and cometary atmospheres. The nature of cometary activity and the thermodynamics of cometary comae will be investigated by studying water excitation in a sample of comets. The D/H ratio, the key parameter for constraining the origin and evolution of Solar System species, will be measured for the first time in a Jupiter-family comet. A comparison with existing and new measurements of D/H in Oort-cloud comets will constrain the composition of pre-solar cometary grains and possibly the dynamics of the protosolar nebula. New measurements of D/H in giant planets, similarly constraining the composition of proto-planetary ices, will be obtained. The D/H and other isotopic ratios, diagnostic of Mars’ atmosphere evolution, will be accurately measured in H2O and CO. The role of water vapor in Mars’ atmospheric chemistry will be studied by monitoring vertical profiles of H2O and HDO and by searching for several other species (and CO and H2O isotopes). A detailed study of the source of water in the upper atmosphere of the Giant Planets and Titan will be performed. By monitoring the water abundance, vertical profile, and input fluxes in the various objects, and when possible with the help of mapping observations, we will discriminate between the possible sources of water in the outer planets (interplanetary dust particles, cometary impacts, and local sources). In addition to these inter-connected objectives, serendipitous searches will enhance our knowledge of the composition of planetary and cometary atmospheres. 相似文献
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《Experimental Astronomy》2009,23(1):221-244
Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space
Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will
enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory.
Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space
very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will
be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical
orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution. 相似文献
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We analyze the statistical properties of normal galaxies to be detected in the all-sky survey by the eROSITA X-ray telescope of the Spectrum-X-Gamma observatory. With the current configuration and parameters of the eROSITA telescope, the sensitivity of a 4-year-long all-sky survey will be ≈10?14 erg s?1 in the 0.5–2 keV band. This will allow ~(1.5–2) × 104 normal galaxies with approximately the same contribution of star-forming and elliptical galaxies to be detected. All galaxies of the X-ray survey are expected to enter into the existing far-infrared (IRAS) or near-infrared (2MASS) catalogs; the sample of star-forming galaxies will be approximately equivalent in sensitivity to the sample of star-forming galaxies in the IRAS catalog of infrared sources. Thus, a large homogeneous sample of normal galaxies with measured X-ray, near-infrared, and far-infrared fluxes will be formed. About 90% of the galaxies in the survey are located within ~200–400 Mpc. A typical (most probable) galaxy will have a luminosity log L X ~ 40.5–41.0, will be located at a distance of ~70–90 Mpc, and will be either a star-forming galaxy with a star formation rate of ~20M ⊙ yr?1 whose X-ray emission is produced by ultraluminous X-ray sources (ULXs) or an elliptical galaxy with amass log M * ~ 11.3 emitting through to a hot interstellar gas. The galaxies within 35 Mpc will collectively contain ~102 ULXs with luminosities log L X > 40, ~80% of whichwill be the only luminous source in the galaxy. Thus, although the angular resolution of the eROSITA telescope is too low for the luminosity function of compact sources in galaxies to be studied in detail, the survey data will allow one to investigate its bright end and, possibly, to impose constraints on the maximum luminosity of ULXs. 相似文献
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程安龙 《地震地磁观测与研究》1993,14(2):54-57
基线值是沟通相对记录与绝对观测的桥梁,是相对记录仪器的工作状态与绝对观测值的准确程度的综合反应,它在地磁台站工作中具有举足轻重的地位和作用。如何准确地、定量地评定基线值的质量,是一个对台站工作有指导意义的重要问题。本文指出多元线性回归方法用于基线值拟合和质量评定的物理机制清楚,计算结果有明确的物理意义。对多项式拟合方法及基线值的温度系数和误差统计的某些观点也进行了讨论。 相似文献
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本文对福建泉州地磁台白水营老址与丰州镇董埔村候选新台址,使用高灵敏度,快速记录的磁通门磁力仪,对台址周围观测环境进行了全面对比监测,从地磁短周期脉冲干扰,地磁场变化形态,日变幅、时均值相关分析等方面进行评估,指出老址的周围环境干扰量已超出0.1nT的<<地磁台站观测规范>>要求,新址符合<<地磁台站观测规范>>要求,适宜建立永久性地磁基本台。 相似文献
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陈伯舫 《地震地磁观测与研究》1998,19(5):51-53
1987年1月28日和29日连续出现赤道逆向电射流。本文对比了这两天9个地磁台的X分量日变化曲线,结果显示琼中台的X日变曲线不受赤道逆向电射流的影响。 相似文献